The present invention relates to disc record systems for use in recording and retrieving information from a disc record and, more particularly, to a cartridge system for protecting the information bearing surfaces of a disc record used in such systems.
High density optical recording systems which may be used for recording and playing back information are known in the prior art. For example, U.S. Pat. No. 4,097,895 entitled, "MULTI-LAYER OPTICAL RECORD" issued to F. W. Spong on June 27, 1978, describes an optical disc record/playback system wherein data is recorded in the form of pits in an absorptive coating on the surface of an optical disc by focusing a high intensity light beam on the surface. For example, in the Spong system, approximately 10.sup.11 bits of information can be stored on one side of a disc-shaped record medium having a 30 cm. diameter.
In optical recording systems involving high density information records, such as the Spong system, dust, finger prints, or the like, or other debris on the information bearing surface of the disc record may adversely affect the operation of the system. Accordingly, it is desirable to provide a disc/cartridge combination wherein the disc record is enclosed in a protective cartridge.
In optical recording or retrieving systems the disc record is positioned on a turntable, or the like, to effect rotational relative motion between the information bearing surface of the disc and the focused light spot. In such systems the disc record should be accurately aligned on the turntable during recording and retrieving operations. Further, the disc record should be pressed positively against the turntable while the turntable rotates.
In optical data processing systems wherein the disc remains in the cartridge during use and storage, it is desirable to facilitate the method and apparatus for holding the disc on the surface. Automatic actuation of the hold-down for holding the record on the turntable is of particular interest with regard to "jukebox" systems, for example, of a type described in U.S. Pat. No. 4,286,790, entitled, "OPTICAL DISC CHANGER APPARATUS" issued to B. W. Siryj et al. on Sept. 1, 1981. In "jukebox" systems a plurality of discs, each enclosed in its respective cartridge, are stored in slots, stacks, or other arrays, permitting any of the plurality of disc/cartridge combinations to be selected out of storage and placed on the turntable. In accordance with the present invention the removal from storage, placement on the turntable and return to storage may be done automatically, or manually, with relative ease and without removing the disc record from the cartridge.